The present invention relates to ties, tie plates, clips and shoulders for incorporation in a rail track. These elements may preferably and advantageously be used in combination, but may be used independently.
In a first aspect, the invention provides a steel tie for incorporation in a rail track, which is a modification of that described in my published application WO 94/28245 and comprises a generally horizontal oblong rectangular plate member for connection transversely of the rail and for restraining vertical rail movement, said oblong plate member having two shorter and two longer sides, each longer side having an outer margin portion inclined downwardly outward relative to the horizontal and a web member extending generally vertically on the underside of the plate member and generally parallel to and spaced inwardly substantially centrally of said longer sides of the plate member and serving to restrain longitudinal rail movement. The margin portions entrance the capture of ballast beneath the tie.
In a further aspect, the invention provides a rail fastening device comprising a pair of opposing longitudinally extending shoulders adapted to accommodate a rail flange therebetween, a downwardly facing abutment surface provided on each shoulder, and a resilient rail clip having an intermediate portion bearing upwardly on said abutment surface, an end portion extending inwardly from said abutment surface and adapted to bear resiliently on an upper side of the flange for restraining the rail against vertical movement, and an outer portion extending outwardly from said abutment surface and curving laterally arcuately outwardly and downwardly toward a lower portion adapted to bear on a bearing surface at a region offset laterally inwardly from a centre of curvature of said outer portion.
This arrangement provides better distribution of stress through the rail clip than known devices of which applicant is aware, and avoid concentrations of stress that may result in failure of the rail fastening device in service. When the above clip in service resists a tendency for the rail flange to lift upwardly, for example to prevent rail roll over, there is a reversal of stress, and hence a point of zero stress in the outer portion between the abutment surface and the lower portions bearing on the bearing surface, and this results in good stress distribution. Having the bearing portion offset laterally inwardly from a centre of curvature of the outer portion results in the clip having increased compliancy, so that installation of the clip is facilitated, and further improves the stress distribution.
In a further aspect, the invention provides a rail retaining device comprising shoulder members for engaging opposite lateral sides of a rail flange, and a rail clip associated with each shoulder member in the form of a bent rod symmetrical about a vertical plane extending laterally of the rail and having an inner portion bearing on the adjacent flange, intermediate limb portions bearing upwardly on a downwardly facing abutment surface provided on the shoulder member and outer portions reacting resiliently on a bearing surface and each comprising a coil spring having a substantial portion thereof extending in a second vertical plane.
The rail clip of this device has the advantage that it is tolerant of dimensional variations in the rail or rail flange, in the shoulder member and in the clip itself, for example arising from manufacturing tolerances, as well as of variations in elevations of the rail flange for example as a result of canting of the rail. The coil spring renders the clip highly compliant. As compared with known bent rod clips of which applicant is aware, the device of the invention greatly reduces the torsional stresses to which the rod is subjected in installation or service.
In a further aspect, the invention provides a rail fastening apparatus comprising a shoulder member engaging at least one side of the rail flange and receiving a rail clip in the form of a resilient rod bent to provide in the installed position limb portions extending transversely of the rail and inner and outer portions adapted to bear on the rail flange and on a bearing surface laterally outwardly of the rail, respectively, said bent rod being generally symmetrical about a vertical plane transverse of the rail, said limb portions comprising an upper pair and a lower pair, and said shoulder member having a reaction surface engaging one of said pairs of limb portions when displaced relative to the shoulder member as a result of upward pressure exerted by said rail flange and displacing said one pair into contact with the other pair to provide a load bearing cross section of increased depth providing increased strength and bending stiffness.
This arrangement allows the rail clip to be formed of relatively thin rod, whereby the clip is made tolerant of dimensional variations, compliant, and relatively easy to install and lightweight and inexpensive to ship. When one pair of the limb portions is displaced into contact with the other, greatly increased strength and resistance to bending is achieved, since the limb portions effectively provide a beam of increased depth of cross-section. As is in itself known, the strength of a beam and its bending stiffness are related to the cube power of the depth of the beam.
In a still further aspect, the invention provides a rail tie plate suitable for attachment to a wood tie, comprising a base plate adapted to be applied to the tie and a pair of abutment members upstanding therefrom to accommodate a rail therebetween and each providing a downwardly facing upper abutment surface for reaction with a laterally inwardly inserted rail clip, and an upwardly facing lower ramp surface inclining from a laterally outer side of each abutment member upwardly inwardly to a laterally inner side thereof for facilitating insertion of the clip to an installed position wherein an inner end of the clip bears resiliently on an inner side of the rail flange.
Whereas known wood tie plates of which applicant is aware have offered difficulties to insertion of rail clips, the ramp surfaces of the above plate facilitate insertion of the rail clip, such as a rail clip as described above, inwardly to an installed position wherein the inner end of the clip bears on a rail flange disposed between the abutment members.
In a further aspect, the invention provides a hook-in shoulder for fastening a rail relative to a horizontal plate member of a tie comprising a shoulder member for bearing toward a rail flange and having a pair of hook-in legs for passing through complimentary apertures in the horizontal plate member of the tie and engaging with the lower side of the horizontal plate member, each shoulder member having an abutment portion upstanding therefrom having an opening therethrough providing a downwardly facing abutment surface for reaction with a rail clip, wherein said abutment portion is box-form and said opening therethrough is bounded by a continuous upper wall providing said downwardly facing abutment surface.
The box form abutment portions offer considerably improved resistance to derailed dragging equipment as compared with known hook-in shoulder members of which applicant is aware.
In a further aspect, the invention provides a hook-in shoulder for fastening a rail relative to a horizontal plate member of a tie comprising a shoulder member for bearing toward a rail flange and having a pair of hook-in legs for passing through complimentary apertures in the horizontal plate member of the tie and engaging with the lower side of the horizontal plate member, each shoulder member having an abutment portion upstanding therefrom having an opening therethrough providing a downwardly facing abutment surface for reaction with a rail clip, and an integral seating portion extending laterally outwardly from the abutment portion and having a lower side bearing on the plate member and an upper side formed with a pit for locating a rail clip.
These shoulders provide a seat for rail clips, such as clips as described above, and facilitate installation and retention of such clips.
In a still further aspect the invention provides a rail retaining device comprising shoulder members for engaging opposite lateral sides of the rail flange, and a rail clip associated with each shoulder member in the form of a bent rod symmetrical about a vertical plane extending laterally of the rail and having an inner portion adapted to engage the adjacent flange, intermediate limb portions adapted to engage upwardly on a downwardly facing abutment surface provided on the shoulder member and outer portions adapted to react on a bearing surface laterally outwardly from the flange and wherein the clip comprises a contact portion varying in width in the direction longitudinally of the rail between the inner and intermediate portions and the shoulder member is adapted to contact said contact portion and resist lateral withdrawal of the clip from the rail.
This device is especially, although not exclusively useful as a zero load retaining device allowing longitudinal movement of the rail relative to the shoulder members but serving to maintain gauge and resist rail rollover.